Stumbled upon this today and was really impressed! It takes tons of things into consideration, from the possibility of pregnancy/breastfeeding to the humidity and temperature around you, to calculate how much water you need to drink today. I hope you find it helpful!

http://nutrition.about.com/library/b...calculator.htm

That was interesting Laurie, thanks.

It put me at 64 ounces of water (not from food). I did answer that I am not in a hot climate because I will be inside today and I'm just going from one air conditioned environment to another.

Sheesh! I need 12 8 oz glasses daily! That's hard for me to do but it's a goal.

It put me at 15.81 8 oz. glasses for the day. Ummmm, I'm going to go with: not possible! Jeez! I'll shoot for 10 8 oz. glasses today!

Mine said I should drink 63oz. of water a day, that's pretty easy, now I just have to DO it!

Makes me want to drink more water with meals...though I really would miss having something with flavor. I do ask for water with lemon at most restaurants.

I find it so much easier to get my water in when I'm at work...I just have my water bottle next to me and sip from it continuously. At home I find much more interesting things to drink or I don't have my water with me...or I'm busy doing stuff. Need to figure out a better way to get my water in at home!

Mine said I had 90+ oz to drink, since I was planning on exercising for a 1/2 hour. That's a lot!

WOW i need to drink a WHOLE lot of water!!!! lol!!! thanks for the site!! it is great!!!

Good lord I need to drink 2 litres of water a day..... I don't even like water. This is a goal I need to work on.

Just a word of warning: it is possible to drink too much water. It's called water poisoning. I have no idea just how much is too much, but be careful!

I'd think a standard 64 oz. a day + 12 oz. for each 30 minutes of exercise would be a good middle road.

It has me drinking less than I already drink- only 3 liters after food. :P I normally drink around 4 with quite a bit of that coming from green, white, and herbal teas. Moving into my dorm, my friends all gawked at my tea collection (I'm at 7 tins of loose leaf, 4 boxes of bagged, about 100 random bags my grandmother gave me, plus all manners of scoops, mugs, and tea balls) but it gets the job done! So does having a sink in my room...

charolastra, I'm the same with with tea, only my collection takes up about three shelves...I probably have over 20 kinds of looseleaf tea and at least 15 boxes of bagged, maybe more. It's such an addiction, isn't it???

You know, my understanding about water poisoning is that it is only a danger if you drink a ton of water at once (that's how the college students died--during a hazing incident that involved chugging water) or if you aren't eating but are sweating and are losing a lot of salt--then you get into a condition where the water is diluting the amount of salt in your body and you get sick. Apparently, this used to happen if people drank water while working hard in the factories, so they were banned from drinking anything at work! Isn't that crazy? Now you can either eat salt, drink something with salt and electrolytes, or, in extreme cases, take salt pills. As long as we're all eating during the day and not drinking all our water at once, we shouldn't have any chance of getting sick, I believe. I'll look around and see if I can find anything online...

Water poisoning is becoming increasingly common in marathons, especially among slower and first-time marathoners. That's people who are out there for five or six hours, so their water problems aren't coming from drinking all at once and in a run that long, they're taking in food/salt as well.

Okay, here we go: http://www.erowid.org/culture/health...oisoning.shtml

Basically what I was saying, but much clearer! They suggest eating salty snacks to help you balance things out if you are drinking huge amounts of water. Honestly, I'd assume that meant drinking gallons a day, not liters. But do make sure you eat and drink the water steadily throughout the day, not all at once!

Good point, Maria! The thing with runners is that they are losing tons of salt through sweat and it's hard to replace that as quick as they are losing it unless they are taking salt pills or drinking only things like Gatorade. I'm not sure about all runners, but the ones I know usually consume things during the race like energy gel, which doesn't have tons of salt. Not sure...but it seems like the problem exists mainly in runners who are new to marathons (assuming they take a lot longer to run the race) and are also drinking too much water during the race. Here's another article just about marathons and water poisoning:
http://www.waterindustry.org/hyponatremia.htm

It's good to be cautious, but letting a fear of water poisoning keep you from consuming a normal amount of water would be a shame. I liked this calculator especially because it was taking so many specific things into account, such as your amount of exercise, the dryness of weather in your area, whether you'd be outside, whether you're pregnant, etc. in calculting your water needs for the day.